Sachusetts



N0. 6|3,647. Patented Nov. I, I898. C. W. BROWN.

INSUL'ATUR FUR INCANDESCENT ELECTRIC LAMPS.

I (Application filed Dec. 15', 1397.) (No Model.)

. E I F6 WITNEEEELE- K 4am UNITED STATES PATENT OFFICEQ CHARLES W.BROl/VN, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, OFONE-HALF TO LAROY S. STARRETT, OF ATHOL, MAS

sAoHUsETrs.

lNSULATOR FOR INCANDESCENT- ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 613,647, dated November1, 1898.

Application filed December 15,1897. Serial No. 661,960- (No model.)

To all whom it may concern.-

Be it known that 1, CHARLES W. BROWN, of Boston, in the county ofSuffolk and State of Massachusetts, have invented a new and usefulImprovement in Insulators for Incandescent Electric Lamps, of which thefollowing, taken in connection with the accompanying drawings, is aspecification.

The object of this invention is to provide for ordinary incandescentelectric lamps of the so-called Edison type an improvedinsulating-sleeve which shall obviate the dangers incident to theexposure of the outer portion of the metallic shell or collar (intowhich I 5 the neck of the bulb is set) to contact with externalconducting substances. The base of this shell or collar isscrew-threaded to engage with the sheet-metal screw-socket of the lamp,both of said parts beingin the electrical 2o circuit, and hencerequiring to be kept free from danger of contact with other conductors.In these lamps as heretofore introduced and now largely used it iscustomary to surround the neck of the bulb and the collar thereon 2 5with a short hard -rubber ring internally threaded to screw upon theoutside of the sheet-metal screw-socket, and thus to insulate theconductors from the metallic bracket or wall-fixture, such ring havingaround its outer margin a radial flange or enlargement which bearsagainst the adjacent surface of the porcelain reflector surrounding thelamp neck or against the outer sleeve of the bracket, so as to hold suchreflector or sleeve in posi- 3 5 tion when the bulb is removed andreplaced. Said ring, however, does not cover the outer portion of theshell or collar fixed on the neck of the bulb, and hence such collar isexposed to accidental metallic contacts, involving fire o risks andother dangers. My improved insulating-sleeve accomplishes perfectly boththese objects and complies with recent requirements of the NationalBoardof Fire Underwriters as to such exposures.

My invention is embodied in a hard-rubber or other non-conductin g tubeinternally screwthreaded to engage with the threaded socket and havingabout mid way of its length a thickened and preferably milled annularportion or shoulder extending outwardly from its periph- 5o cry to bearagainst the reflector or the bracketsleeve, the tubular body extendingabove and below said shoulder or annular portion. By preference I makethese projecting end portions about equally thin, so that either endwill pass through the central opening in the reflector and enter betweenthe bracket-sleeve and the threaded socket, making the devicereversible. I provide also a supplementary washer slipped over thereduced end of the insulator, between the shoulder and the reflector,when desired.

In the drawings, Figure 1 represents a lamp provided with one ofmyimproved insulators, shown in longitudinal section. Figs. 2 and 3represent the insulator in perspective and in longitudinal section, andFig. 4 shows it provided with a supplementary ring. Fig. 5 is a modifiedform in which the enlargement extends to the outer end. Fig. 6 shows thesupplementary ring detached.

A represents the neck of the lamp-bulb, provided with thepermanently-affixed collar B, having a spiral corrugation or coarsescrewthread extending about two thirds of its length.

O is the usual sheet-metal screw-socket into which the threaded end ofthe shell or collar B is screwed.

D is my improved insulator, internally 8o threaded to screw upon theexterior of the threaded socket O and formed midway of its length withthe raised external shoulder or ring D, serving to hold the reflector Ein place and as a stop to prevent screwing the insulator in too far. Theouter end of the device extends beyond and effectually covers andinsulates the metallic collar B, thus preventing contact of anyelectrical conductors therewith. The end portions being much 0 thinnerthan the ring D, either end may screw in between the socket O and thesurrounding portion F of the metal bracket, while the other extends overthe outer end of the collar B and around the lamp-neck. The 5 outer endof the insulator may be as thick as the ring D, as shown in Fig. 5; butmaterial is saved and the appearance improved by making it as shown inthe other figures. The relative dimensions of these end portions mayvary so long as one of them covers the outer part of the collar B, Whilethe other insulates the lamp from the bracket. In some cases I provide asuitable washer G, surrounding the reduced end of the insulator betweenthe ring D and the face of the reflector. This Washer I use when thereflector is omitted or in cases where the metal shell or collar B ofthe lamp is of unusual length, my insulator being thus held somewhatfarther out 011 the neck of the lamp.

I claim as my invention 1. The described reversible insulator formed ofnon-conducting material internally threaded, having about centrally athickened peripheral ring and at either side thereof thinner endportions projecting longitudinally from and of less diameter than saidring, substantially as set forth.

2. The lamp A with fixed collar B and wallsocket C in the electriccircuit, in combination with the tubular insulator D D of such length asto cover the outer portion of the collar and extend between said collarand the bracket-sleeve F, and with the supplementary Washer G adjacentto the shoulder D, substantially as set forth.

3. The incandescent lamp A with its threaded shell or collar 13, thesheet-metal screwsocket O and the bracket-sleeve F, in combination withthe threaded non conducting tube D formed with the radial shoulder Dadapted to support the reflector E, and with the projecting endsrespectively insulating said sleeve from the socket and the outer end ofsaid collar from external conductors, substantially as set forth.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, on this 4th day of December, A.D. 1897.

CHARLES W. BBOVVN.

WVitnesses A. H. SPENCER, lI. -W. LADD.

